Simple mole fraction question

This is for my chemical engineering class...for some reason, I am struggling with this problem. I'm not quite sure how to connect the dots..I feel like I know how to do this, though.

1. The problem statement, all variables and given/known data
The mass fraction of benzene in a benzene-toluene mixture is 0.450. What is the mole fraction of toluene in the mixture? Molecular weights of benzene and toluene are 78.11 and 92.12 respectively.

2. Relevant equations
listed

3. The attempt at a solution

Mass fraction of toluene is .550

Now, that is dimensionless, and I don't know how to get going from here. I know it's simple, but I've forgotten my general chemistry...
I was thinking I just multiply that mass fraction by the molecular weight of toluene, but then that's still in g/mol...then I thought about adding them, which would make more sense (since I have the mass fraction). I dunno though, because I don't have the exact chemical formula.

they give you the molecular weights of each component, and you can find the molecular weight of the mixture by just adding the molecular weights.

since the masses are in grams, and moelcular weight is in g/mol, if you divide the mass by molecular weight you get just moles. just make sure what you do to one side of the equation you do to the other.

And then just manipulate the equation the same way you did to get the mass fraction of toluene.